ZOOL— Vol. III.] STEVENS— CILIATE INFUSORIA. 13 



along the neck groove toward the mouth, and the greater 

 rapidity of its vibration when the animal is swimming may 

 indicate some locomotor function. 



Vacuoles. — This species has no contractile vacuole, agree- 

 ing in this respect with the forms described by Claparede, 

 Fabre-Domergue, Gruber, and Wallengren, while Claus and 

 Cohn figure such a vacuole on the right side of the body 

 in the mouth region. Food masses enter the entoplasm 

 at the extremity of the conical pharynx, pass posteriorly 

 and accumulate in the region posterior to the mouth (figs. 

 2 and 3), though in some full fed specimens a few food 

 vacuoles are seen on the right side above the mouth; 

 but they never pass into the neck or attachment disc, 

 which are therefore more transparent than the oral disc. 

 The animal is exceedingly well provided for in the way of 

 apparatus for carrying food particles to its mouth — oral 

 cilia, ciliary membranes, vibratile neck membrane and ven- 

 tral neck groove all contributing to that end. No anus has 

 been detected. The food masses consist of diatoms, other 

 infusoria, and of what appear to be either leucocytes or 

 loosened epithelial cells from the host. The whole poste- 

 rior half of the oral disc is often filled with yellowish brown 

 diatom masses; shells of navicula, extending half way across 

 the disc, are frequently seen (fig. 2) . 



Nuclei. — In the adult form of this Licnofhora there is 

 found to the right of the axial neck fibre, very near its point 

 of union with the base of the attachment cup, a small spher- 

 ical body which stains deeply with iron-h^matoxyhn, but 

 destains much more easily than the neck fibres or macro- 

 nuclei and does not readily take nuclear stains. Its diam- 

 eter is about 2 yu. but increases to 3 ^tt in division stages. Its 

 structure is homogeneous. Its behavior in division, increas- 

 ing in size and becoming less stainable, as do the micro- 

 nuclei of Stento?', as described by Johnson (1893), leads 

 one to think that this body is a micronucleus, but the phe- 

 nomena of conjugation which should establish its nature 

 and function have not yet been observed (figs. 4, 7, 13, 

 14, n""). 



